1. Field of the Invention
The present invention relates to an ink jet printing apparatus on which a head cartridge equipped with a printing head is mounted to be detachable with respect to a carriage, and an ink tank is mounted to be replaceable with respect to the head cartridge.
2. Description of the Related Art
As a printing apparatus, there is a printing apparatus having functions such as printing, copying, facsimiling or the like, or a printing apparatus used for an outputting apparatus of complex electronic hardware including a computer, word processor or the like, and a printing apparatus used for an outputting apparatus of a workstation. Such a printing apparatus is constructed so that it can print an image on printing material (printing medium) such as paper, plastic thin plates or the like based on image information.
And, the printing apparatus can be classified as an ink jet method, a wire dot method, a thermal method, a laser beam method or the like depending on its printing method. Among these, since the inkjet method, in particular, can make a printing image high in image quality, and realize a low running cost, it has become widely popular in general households in recent years. In conjunction with this, it has been demanded that the printing apparatus is to be downsized and light in weight. Normally, the printing head of the printing apparatus of a popular type ink jet method (ink jet printing apparatus) like this is mounted to be detachable on a head mounting portion (in a serial scan type printing apparatus, carriage) of the printing apparatus for maintenance or the like. A detachable mechanism serving as the printing head in the head mounting portion is required to be easily detachable in construction limiting mistakes by the user as much as possible.
Japanese Patent Laid-Open No. 2004-090343 discloses an ink jet printing apparatus of a serial scan type on which the head cartridge equipped with the printing head is mounted to be detachable with respect to a carriage, furthermore, an ink tank is mounted to be replaceable with respect to the head cartridge. The carriage is equipped with a lever which is operated when attaching/removing the head cartridge. After mounting of the head cartridge on the carriage, by operating the lever in one direction, the head cartridge is fixed to the carriage, and a contact of a head cartridge side is pressed to a contact of carriage side, therefore, they are electrically connected. By operating the lever in the other direction, the contact of the head cartridge side is released from the contact of the carriage side, and the head cartridge can be removed from the carriage.
However, in the printing apparatus constructed like this, when removing the ink tank from the head cartridge, users may operate the lever by mistake to induce the head cartridge to be removed from the carriage. In comparison with a replacement frequency of the ink tank, a replacement frequency of the head cartridge is extremely low. And, when removing the head cartridge from the carriage, the printing head equipped on the head cartridge may be damaged during performance by environmental changes and contact with peripherals.
From such a point of view, some printing apparatuses, in recent years, have constructions equipped to limit operation of the lever in the other direction so that the lever cannot be completely operated in the other direction unless the ink tank is removed from the head cartridge. Unless the lever can be completely operated in the other direction, although a pressing force of the contact of the head cartridge side with respect to the contact of the carriage side loosens, the head cartridge cannot be removed. By enabling a detachment of the head cartridge as a condition for removing the ink tank like this, a situation in which users can remove the head cartridge by mistake can be avoided in advance.
However, when limiting the operation of the lever in the other direction as mentioned above, although the head cartridge cannot be removed, the pressing force of the contact of the head cartridge with respect to the contact of the carriage side becomes loose. Therefore, because those contacts separate, they may not be maintained in an electrically conductive state.
Since a contact between the carriage side and the head cartridge side is important so as to transmit a drive signal of the printing head or the like, those contacts, therefore, are preferably prevented from wear by maintaining the electrically conductive state.